![]() In 20, AVIRIS-NG was flown over 22,000 square miles (57,000 square kilometers) of the state as part of the California Methane Survey. Attached to the bottom of an aircraft, the instrument can detect greenhouse gas emissions from individual facilities or even pieces of equipment by looking at how the gases absorb sunlight. Rather than analyzing data from ground sensors, the study focusing on oil refineries uses measurements made by an imaging spectrometer called AVIRIS-NG (Airborne Visible/Infrared Imaging Spectrometer-Next Generation). It found large reductions in overall emission rates. Improved infrastructure at a massive waste site near Granada Hills likely also played a role.Ī March 2023 study by JPL researchers compared methane emissions in 2020, early in the COVID-19 pandemic, from both oil fields in the San Joaquin Valley and refineries and power plants in Los Angeles County to emissions measured in 2016-17. Then, using a mathematical model to estimate the emissions decrease, Yadav and colleagues found the areas covered by the Granada Hills and Ontario sensors accounted for much of the drop in annual emissions from 2015 to 2020.Īlthough the paper doesn’t cite causes of the emission reductions in those two locales, Yadav suspects they resulted from better management of natural gas pipelines and equipment, which in turn led to lower fugitive – or accidental – methane releases. ![]() The researchers found that month-to-month fluctuations in methane concentrations measured at each sensor tower gradually fell from 2015 to 2020 and well into 2022 – a strong indication that local emissions of the gas were also decreasing. It also extends south through all of Orange County. The sensors have been gathering data across a large swath of Southern California since 2015 and enabled researchers to study an area that stretches from the beaches of Malibu in the west to the mountains and deserts of San Bernardino and Riverside counties in the east. Yadav’s paper is based on measurements from eight spectroscopic sensors that were installed as part of the Megacities Carbon Project, a multiagency collaboration currently monitoring greenhouse gases in the Los Angeles, Indianapolis, and Washington areas. “If you are turning the information over to decision-makers, you have to be sure.” Focusing on the Region “The important thing is to determine whether emissions are increasing or declining, and for that it’s helpful to have more than one approach,” said Yadav, whose study employs two techniques. That two studies could use different techniques to identify and quantify emissions trends is crucial for generating confidence in the conclusions drawn from methane observations, added Vineet Yadav, a JPL data scientist and lead author of the first paper. “These papers demonstrate that methane reductions are not only possible, they’re measurable through persistent monitoring,” said Andrew Thorpe, lead author of the COVID-period study and a JPL research technologist. Therefore, reducing human-caused emissions of the gas is a particularly effective way to make significant, short-term impacts on global climate change. Methane has a much shorter atmospheric lifespan than carbon dioxide – around 12 years, compared to centuries for carbon dioxide – but it absorbs much more energy while it exists in the atmosphere. A February 2023 study by JPL researchers estimated that annual methane emissions in the Los Angeles Basin fell by about 7%, or 33 million pounds (15 million kilograms), possibly due to better management of natural gas pipelines and equipment as well as improved infrastructure at a large landfill.
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